New Users
New users can download and install the 20120125 ISO image using the instructions here. The step marked "Install Security Onion updates" will automatically install this update.

In-place Upgrade
Existing Security Onion users can perform an in-place upgrade using the following command (if you're behind a proxy, remember to set your proxy variables as described in the Proxy page of our FAQ):

Security Onion

Security Onion is a Linux distro for intrusion detection, network security monitoring, and log management. It's based on Ubuntu and contains Snort, Suricata, Bro, OSSEC, Sguil, Squert, ELSA, Xplico, NetworkMiner, and many other security tools. The easy-to-use Setup wizard allows you to build an army of distributed sensors for your enterprise in minutes!